We are developing an ultra wideband (UWB) radar sensor payload for the man-portable iRobot PackBot UGV. Our goal
is to develop a sensor array that will allow the PackBot to navigate autonomously through foliage (such as tall grass)
while avoiding obstacles and building a map of the terrain. We plan to use UWB radars in conjunction with other
sensors such as LIDAR and vision. We propose an algorithm for using polarimetric (dual-polarization) radar arrays to
classify radar returns as either vertically-aligned foliage or solid objects based on their differential reflectivity, a function
of their aspect ratio. We have conducted preliminary experiments to measure the ability of UWB radars to detect solid
objects through foliage. Our initial results indicate that UWB radars are very effective at penetrating sparse foliage, but
less effective at penetrating dense foliage.